Chapter 7: Proteins Flashcards
describe the structure of a protein
Folded amino acid chains
describe the structure of an amino acid
Amino acids have 3 main groups
- Nitrogen containing amine group
- Carboxylic acid
- Side chain (Rx)
How many different amino acids are there?
21
Describe the primary protein structure
Amino acids bind together through peptide bonds to form a polypeptide (releases a water molecule)
Not yet a protein (must fold into next level of structure)
Describe the secondary protein structure
Hydrogen bonds between non-adjacent amino acids lead to the formation of alpha helices and beta-pleated sheets
Describe the tertiary protein structure
Interactions between amino acids side chains lead to further folding of the polypeptide chain; May result in a functional protein
Describe the quaternary protein structure
Several proteins in their tertiary structure bind to form a final protein; each one is called a protein subunit
How many amino acids are essential?
9
define: transamination
Process of making non-essential amino acids by modifying other amino acids
Define: conditionally essential amino acids
Conditionally essential amino acids: non-essential amino acids that become essential when the body cannot synthesize enough of them
Define: complete proteins and the sources
Complete proteins: foods that have all nine essential amino acids
- All animal sources and soy, quinoa, and buckwheat
Define: incomplete proteins and the sources
Incomplete proteins: foods missing 1 or more essential amino acids
- Plant sources
- The missing amino acids are called the limiting amino acid(s)
- Lysine is usually the limiting amino acid
What do animal sources of protein also have in terms of nutritional value?
- Have B vitamins, iron, zinc, calcium
- Lower in fiber, higher in saturated fat and cholesterol ( which increases risk of heart disease)
What do plant sources of protein also have in terms of nutritional value?
- Contain some B vitamins, iron, zinc, calcium
- Higher in fiber, unsaturated fats, and phytochemicals
What is the idea behind complementing proteins?
- Consuming a variety of foods to get all your amino acids
Define: amino acid pool
where we take amino acids from to compose a protein
Define: denatured protein
Denatured protein: lacks 3d structure and loses function
How does a denatured protein occur
Acids, heat, agitation all denature proteins